Separation of immiscible liquids



June 5, 1951 J. W. ROBINSON SEPARATION OF IMMISCIBLE LIQUIDS 2Sheets-Sheet 2 IIIIII l w M Sf W s 1 i m i 67 Si i f5 y 73 ze' INVENoR.LUM

Patented June 5, 1951 UNITED STATES PATENT OFFICE.

SEPARATION F IMMISCIBLE LIQUIDS John Warren Robinson, Mcrchantville, N.J., assignor to Selas Corporation of America, Philadelphia, Pa., acorporation of Pennsylvania Application February 23, 1946, Serial No.649,512

(Cl. ZIO-44) Claims. 1

My invention relates to phase separation of im'miscible liquids, and isconcerned with an improvement for effecting such phase separationrapidly and efficiently without the aid of centrifugal apparatus.

In many instances it is necessary to separate from a body of liquidforming a continuous phase particles of another liquid forming adispersed phase, such liquid particles being dis-- tributed in the bodyof liquid forming the continuous phase and immiscible therewith. It hasalready been proposed to effect phase separation of such immiscibleliquids with the aid of a porous wall member which is formed withcapillary passages and pervious to the liquid forming the continuousphase. When phase separation is effected in this manner the pressuredifferen tial produced across such porous wall member is. dependent,among other things, upon the interfacial tension between the liquids tobe separated.` While the liquid forming the continuous phase is flowingthrough the porous wall member which is pervious to such liquid, theliquid particles of the dispersed phase are prevented from flowingthrough the capillary passages thereof by the interfacial tensionbetween the-liquids at the inlets of the capillary passages,

It is an object of my'invention to provide an improvement for separatingimmiscible liquids with the aid of porous wall members of this type,particularly to present to the mixture of liquids to be separated amaximum overall area of capillary wall surfaces which occupies a minimumamount of space. More. particularly, it is an object to embody such alarge area of capillary wall surface ina single element or member'whichis easily and readily removable for cleaning and replacement. Ipreferably accomplish this in sucha Way that the separating unitV inwhich the porous member or members are embodied may be removed from andreinserted in position without disturbing the connections to the deviceor apparatus.

In many instances it is necessary to separate a dispersed phase, such aswater, for example, from an emulsion. in which iine particles of thedispersed phase are distributed in a body of liquid forming thecontinuous phase, such as oil, for example. While separation of Suchimmiscible liquids can be effected with the aid of porous members of thetype just described, the fact that the porous members must effect all ofthe coalescing and agglomerating action of the dispersed material, inaddition to separating such material from the liquid forming the cori-rtinuous phase, imposes an unduly heavy task upon the porous members.This is so because the slugs or droplets of the dispersed liquid, whichcoalesce and form only on the surfaces of the porous members, tends toreduce the overall effective surface area of the porous mem# bers atwhich simple phase separation 0f the immiscible liquids is ordinarilyaccomplished. The work imposed upon the porous members to effect phaseseparation of the dispersed material in an emulsion is also madeespecially difcult when foreign solid matter is present and exercises astabilizing action on the emulsion. ,In such cases, the emulsion isusually referredv to as being dirt stabilized and exceedingly difficultto? cause coalescing of the dispersed materialand break up the emulsion.l

It is a further object ci the invention to improve the operation ofliquid separatingrunits of this type for separating the dispersed phaseof an emulsion, This is accomplished by providing a filtering unit whichVcooperates and works with the separating unit by first agglomerating orcoalescing a substantial fraction of the dispersed material before themixture of liquids contacts the porous member or members of theseparating unit. The nal or residual coalescing of the dispersed phasecan be readily accomplished at the surfaces of the porous mem ber ormembers of the separating unit without unduly impairing the efliciencyof such porous members in effecting phase separation yof the iinmiscibleliquids, Such initial iiltering of the emulsion is preferablyaccomplished with the aid of a mat formed of mineral fibers, such asglass, for example, which are loosely packed to provide a nltering andcoalescingl element having the appearance of a felt-like pad and formed.with capillary passages. It has been found that such a iiltering elementis highly effective in promoting the coalescing or agglomerating actionof the dispersed material, particularly when an emulsion is dirtstabilized and ordinarily diflicult to break up. To promote thecoalescing action, the fibers of the filtering element must be wettableby the particles of liquid forming the dispersed phase when suchparticles are in the presence of the liquid forming the continuousphase, A filtering element of this kind has been found highly, effectivefor removing foreign solids from emulsions, thereby rendering theemulsions less stabilized which in turn promotes the coalescing actionthat takes place duri-ng passage of the emulsion through the capillarypassages of the element.

It is a still further object of the invention to provide a filtering andcoalescing unit ahead of a liquid separating unit in such a manner thata patch of flow for the liquid is provided between these units in whichseparation of the coalesced droplets or bodies of the dispersed materialis accomplished by difference of specific gravity, whereby a substantialfraction of the dispersed material may be removed from the mixture ofimmiscible liquids to reduce the amount of coalescing work imposed uponthe porous wall members of the liquid separating unit and speed up theseparation of the immiscible liquids. This is preferably accomplished byconstructing the filtering unit in such a way that the path of ow forthe mixture in which separation of the dispersed material takes place bydifference in specific gravity is practically no i greater in lengththan the filtering and coalescing unit itself, thereby providing acombined ccalescing unit and liquid separating unit which is compact andrelatively small in size and requires a minimum amount of space in use.

The novel features which I believe to be characteristic of my inventionare set forth with particularly in the claims. The invention, both as toorganization and method, together with the above and further objects andadvantages f thereof, will be better understood by reference to thefollowing description taken in connection with the accompanying drawingsformingapart of this specification, and of which:

Fig. l is a vertical sectional view of apparatus embodying the inventionincluding a liquid separating unit and a liquid filtering and coalescingunit;

Fig. 2 isa fragmentary enlarged horizontal sectional view of the liquidseparating unit of Fig. 1;

Figs. 3 and 4 are perspective views of parts of the apparatus shown inFigs. 1 and 2 to illustrate details of the liquid separating unit;

Fig. 5 is a sectional View, taken on line 5-5 of Fig. 1, to illustratethe filtering unit more clearly; and

Fig. 6 is a fragmentary vertical sectional view illustrating amodification of the apparatus shown in Fig. 1.

In Fig. 1 is illustrated apparatus I3 embodying the vinventioncomprising an outer shell I I including a central section I2 and endsections I4 and I5 removably connected thereto at IG and I1,respectively. The central section I2 and end section I4 are formed withvent openings I 8 having removable closure members I9 for a purposewhich will be described hereinafter'. The end section I4 is cup-shapedand forms an end cover for one end of the shell I I, while the oppositeend section I5 is provided with an end plate 20 which is removablysecured thereto at 2 I.

Within the end section I4 and also a part of the central section I 2 ofthe casing I I is provided a filtering and coalescing unit 22 forremoving foreign solids and effecting a coalescing or agglomeratingaction of the dispersed phase of an emulsion adapted to be suppliedunder pressure to theapparatus I 0 through a conduit 23 connected tov aninlet 24. The filtering and coalescing unit 22 comprises an elongatedhollow member composed of a pair of tubular sleeves 25 and 25a that arejoined together by a perforated tube or cylinder 29 which may be formedof expanded metal. It will be seen that sleeve 25 is fastened kll toflange 21 as by welding. Cylinder 29 is fastened to both sleeve 25 andsleeve 25a and sleeve 25a is closed on its left end by a cap y26. Theseparts provide a rigid, unitary member. The hollow member cooperates withthe outer shell to form a space 28 around its exterior which may bereferred to as an inlet space.

A body of porous material is disposed about and completely envelops theperforate section 29 of the hollow member. As shown, the porous materialcomprises a mat 30 of loosely packed bers formed as an open-ended sleevewhich may be slipped into position over the closed end 26 of the hollowmember, so as to overlie the perforate section 29. Such a mat 3D may beformed of mineral fibers, such as glass or the like, for example, whichare loosely packed to provide la porous element having capillarypassages therein. The mat 30 is of greater length than the perforatesection 29 so that the ends thereof may be tightly fixed in position bysuitable removable clamping rings 3| which act against the sleeves 25and 25a. In order to protect the underside of the mat 30 from theperforate section 29, fine mesh screening 32 may be wrapped 'about theperforate section against which the mat 30 i adapted to bear.

Within the hollow member and spaced therefrom is a hollow open-endedsleeve 33 having one open end vclosely adjacent to and spaced from thevclosed end 26 of the hollow member. The opposite open endA of thesleeve 33 is secured to the inner peripheral edge of the flange 21,l

thereby supporting the sleeve 33in a cantilever fashion in the samemanner 'that the hollow member 25 is supported, as previously described.

The open end of the sleeve 33 kat the flange'21 communicates with theinterior of the` central section I2 of the shell I I. lowY sleeve 33 andthe interior of the central'section I2 together form a chamber 34 whichis.-

separated from the inlet space 28 by a partition including the porousmat 30. Within the enlarged end of chamber 34 formed by the centralsection I2 of the shell is provided a liquid separating unit 35.

The liquid separating unit 35 at one end is provided with an enlargedend plate 36 which is secured at its outer peripheral edge portion, asby bolts 31, for example, to the flanged end of the central section I2of the shell. The unit 35, which is supported in a cantilever fashion atone end at the end plate 36, comprisesr two groups o f annular-shapedspacer elements or rings 38 and 39 which are shown most clearly in Figs.3 and 4.

The spacer elements 38 and 39 are alternately' stacked in end to endVrelation, a sheet 49 of porous material being disposed between each pairof adjacent elements 38 and 39.

like the other elements 38 and differs therefrom by having a wall at oneface thereof to form a and 39 are in alignment and, together withsimilarly distributed apertures in the porous sheets- 49, form elongatedopenings through which extend tie-bolts 42 threaded at opposite ends toreceive tightening nuts l43. The end plate 36 isrv also formed withthree spaced apart apertures which are in alignment with the apertured-Essentially, the hol- The end spacerv velement 38a nearest to the sleeve33 is generally bosses. 4l and. through which the tie-bolts, 42. extendat one end to receive one set of the tighten-` ing nuts 43..

The two groups of spacer elementsl 38 and 39A and sheets 48: of porousmaterial therebetween form a row'of compartments. and 45, each com,-partment 45 being disposed between adjacent. compartments. 4.4:. Eachcompartment 44', ex:- cept the end. compartment, is. defined by a spacerelement or ring 3.81y and the porous sheets 40' held against theopposing faces thereof.` One; end: compartment 44; is defined by the endspacer ele ment 38a` and the porous sheet. 4.!! held against-` the innerface thereof, and ther opposite end corninto which the mixture cfimmiscible liquids is:

adapted to pass from chamber 34 through suit-4y able inlets or elongatedslots 46 formed. in end to end relation about the circumference ol eachspacer element 39. As will be explained Ipresentlygthe porous sheets 40areY pervious` only to one of the liquids in the mixture passing intothe compartments 45, and the liquid to which the porous she-ets arepervious ows therethrough into the compartments 44. The spacer elements38 dening the compartments 44 are formed with inwardly extendingapertured bosses 41f which are recessed or slotted at 48 intermediatethe outer faces thereof, as best shown in Fig. 3, sothat the liquidflowing into the compartments 4t can pass through the slots 48 into theapertures formed in the bosses 41.

The apertured bosses 41 of' the spacer elements 38 are in alignment withand contiguous to inwardly extending apertured bosses 5f formed on thespacer elements 39 defining the comparte ments and the porous sheets 46are provided with openings at the regionsl of the apertured bosses 41and 49, so` as to form a manifold 5i at the bottom part of the liquidseparating unit 35 which extends from the end spacer element 38a throughan opening 52 in the end plate 36.`

The separated liquid in the compartments 44 can only pass through theslots 48 of spacer ele'- ments 38 into the apertures in bosses 41 whichformed a part of the manifold 5|. Since the apertures in bosses 49 ofthe spacer elements 39 member is discharged through the manifold 5I intoan end chamber 53 formed by the end sec-V tion I5 of the shell Il.. Theliquid in chamber 53 is discharged from the apparatus Hl through anoutlet 54 to which is connected adischarge conduitv 55. A second outlet56 having a removable closure member 51 is provided for the chamber 53diametrically opposite the outlet 54 for a purpose which will bedescribed presently.

They shell Il is provided with two downwardly depending` vessels 5.8.and` 58;, one, of; which opens into the inlet, space 28. and the otherof which opens into the chamber 3.4 at the region of theV liquidseparating unit, 3.5 just described. The. liquid which is held back bythe apparatus. I8 collects in the vessels 58 and 59, as will bedescribed presently, and removable drain plugs. 68: and SII are providedfor these vessels to remove from time.- to time the. liquid collectingtherein.

`When the apparatus lll just. described is eme played to separate adispersed phase from an emulsion in which fine particles of a liquidtorming suc-h dispersed phase are. distributed in a liquid forming avcontinuous phase, the mixture of immiscible liquids forming suchemulsion is supplied under pressure through the conduit` 24 to the inletspace 2.8. After the apparatus has been in operation for a period oftime, the inlet space4 28 and vessel 58 communicating therewith areentirely filled with the mixture of immiscibl'e liquids` lintroducedtherein. Tol permit air trapped in the inlet space to be vented there-Afrom, the closure member ISl may be temporarily removed from the ventopening I8 in the end section I4, so that the hollow member 25 will-becompletely enveloped by the mixture.

Thel mixture forming the emulsion is intro-r duced into the inlet space28 under sufficient.

pressure to cause the mixture to pass through the capillary passages ofthe mat 30 into the annular space 62 formed between the hollow member 25and sleeve. 33. The mat 30 is formed of material possessing suchphysical properties that it is preferentially wetted by the liquidforming the dispersed phase when in the presence of the continuousphase. l Thus, when iine` particles of Water are dispersed in ahydrocarbon liquid forming the con-` tinuous phase of an emulsion, forexample, the mat 30 is formed of a hydrophilic material which ispreferentially water wetted in the presence of hydrocarbon liquid. Insuch case the brous mat 3U may be formed of a material, such as glassfibers and the like, or any other suitable hydrophilic material wellknown in the art'.

liquid are dispersed in water or an aqueous solution forming thecontinuous phase of an emulsion, the mat 3U is rendered hydrophobic `sothat it is preferentially oil wetted in the presence of, Water.

the like, which has been treated in any suitable manner well known inthe art to renderthe man terial hydrophobic or water repelian't. Forexample,l the material forming the mat 33 may be rendered hydrophobic bytreating suc-h material with silicones or with a composition comprisingan organo-silicon halide, as disclosed in Pat-node Patent No. 2,306,222.7

During passage of the emulsion through the fibrous material forming themat 30, the indi"-y vidual fibers become wetted by the Afine particlesof liquid forming the dispersed phase of the;

emulsion, inasmuch as the material of the mat is preferentially wettedby such dispersed phase.

The fine particles of liquid forming the dispersedl phase build up atthe surfaces of the individual fibers, thereby coalescing andagglomerating the fine liquid particles into larger particles to formdroplets or slugs of liquid which are mechanically disruptedor'dislodged' from the fibers and passT into the annular space 62. y

i. I have found that a mat 30 formed of fibrous material, such as glassand the like for example,

Con-f vers'ely, when fine particles of a hydrocarbon In such oase thefibrous mat 30 may be' formed of' a material, such'as glass fibers andis Aparticularly effective for coalescing or agglomerating the fineparticles of liquid forming the dispersed phase of an emulsion, eitherwhen such material is untreated and inherently preferentially waterwetted or when treatedso as to be preferentially oil wetted. When themat 30 is formed of loosely packed mineral fibers which are relativelylong and of an average thickness of. about one micron, a body of porousmaterial is provided having capillary passages therein which not onlyiseffective to coalesce or agglomerate the dispersed material but ishighly efficient as a ltering medium to remove solid foreign matterVfrom emulsions., Since foreign solids often tend to stabilize emulsions,the effective removal of foreign solid matter renders the emulsions lessstabilized in this respect and promotes the coalescing action whichvtakes place during passage' of the emulsion through the capillarypassages.

in the mat 30.

lThe-initial coalescing or agglomerating action' pass lfrom the space 62into the interior of the' central section I2 of the shell I I.

The mixture in the annular space 62 flows toward the closed end 26 ofthe hollow member 25. The mixture then reverses its direction ofmovement and passes into the sleeve 33 and interior of the centralsection I2 of the shell. After the apparatus has been operated for aperiod of time the sleeve 33, the interior of central section I2 andvessel 59 communicating with the latter be- When the apparatus I isinitially placed in operation the recome filled with the mixture.

movable closure members I9 for the vent openings I8 in the centralsection I2 may be removed sufficiently long to permit trapped air toescape from the interior of the central section I2, so that the mixturewill completely envelop the separating unit 35 and fill the spaceinwhich it is disposed. v

The sleeve 33 and interior of the central section I2, which togetherprovide the chamber 34, form a horizontally extending path of flow forthe mixture from the discharge side of mat 30 to the liquid separatingunit 35. 'Ihe mixture in chamber 34 passes through the inlets 46 of theliquid separating unit 35 into the inlet compartments 45 at whichregions the mixture is brought into physical contact with the poroussheets 40.

In each instance, the sheets 40 employed are pervious to the liquidforming the continuous phase of the mixture and impervious to the liquidparticles forming the dispersed phase. The liquid passing through thesheets 40 enters the compartments 44 and thence flows into the aperturedbosses 41 of spacer elements 38 through the slots 48 formed in suchbosses. The liquid forming the continuous phase then passes through themanifold I in the lower part of the separating unit 35 into vthe endchamber 53. From chamber 53 the liquid is discharged from the apparatusI0 through the outlet connection 55. By providing such outlet connectionat the upper part of chamber 53, this chamber as well as the comthemixture after the apparatus has been in operation fora period of time.

Although not to be limited thereto, the porous membranes or wall membersin the liquid separating unit 35 may comprise' sheets of closely wovenmaterial, such as glass or the like, for example, to provide a number ofporous walls having capillary passages. When the liquid forming thecontinuous phase of the mixture is water or an aqueous solution, theporous sheets are formed of material which is hydrophilic andpreferentially Water wetted. `Sheets 40 formed of glass cloth and thelike are preferentially water wetted and, upon once being wettedbywater, prevent flow therethrough of another liquid immiscible therewith.Conversely, lwhen a hydrocarbon liquid forms the continuous phase of themixture, the sheets employed are preferentially oil wetted andhydrophobic. When the sheets are formed of Woven glass cloth and thelike, such sheets may be rendered hydrophobic or water repellant bytreating the material with silicones or a composition comprising anorgano-silicon halide, as explained above, or in any other suitablemanner wellrknown in the art. When heat curing silicones are employed torender sheets of closelyl woven glass cloth water repellant, thesurfacesproduced on the sheets are hard and insoluble in hydrocarbonliquids. Y

Let vus suppose that the sheets 40 are rendered hydrophobic and waterrepellantso that the capillary passages are readily wetted by ahydrocarbon liquid. In such case the hydrocarbon liquidv forming thecontinuous phase is in intimate contact with the walls of each capillarypassage in the sheets 40 and the surface immediately surrounding itsinlet or entrance opening. There isvv interface into the capillaryentrance. The extentto which the hydrocarbon liquid-water interfacebulges is opposed or resisted by a force at the interface of the twoliquids which is dependent upon and developed by the interfacial tensionof the liquids.

The resisting force which is developed by the interfacial tension at theinlet of each capillary passage is dependent upon the perimeter of thepassage at its inlet. A critical or rupture pressure is reached when thepressure differential across the sheets 40 increases to cause such`bulging and distension of the interfacial surface, at the points ofyield at the inlet of the capillary passage,A that the interfacialsurface becomes substantially parallel to the axis of the capillarypassage at which time the water or liquid normally held back will beginto flow through the capillary passage,

So long as the pressure differential across the sheets does not exceed apredetermined maximum? value, which has just been referred to as therupture pressure, the interface between the immiscible liquids at theinlets of the capillary passages will not be ruptured and thehydrocarbon liquid in the passages will not be displaced by water. Therupture pressure is dependent upon several factors including theinterfacial tension of the liquids and the maximum size cap-i illarypassage. The rupture pressure increases` for liquids having a higherinterfacial tension value; and is inversely proportional to pore size Yanddecreaseswith increase in the maximum size capillary passage.

VIheapparatus is positioned as shown in Fig. 1 when the specic gravityof the liquid Vforming the dispersed phase is greater than that lof theliquid forming the continuous phase. In such case the ne particles o'fthe heavier dispersed material coalesce at the sheets '40 to `formlarger particles or coalesced `bodies of liquid which f all v4byjgravityto the bottom of chamber -34 and into rthe collecting vessel 59. Byproviding a number of 'elongated lslots 46 in end to end relation aboutythe periphery of each spacer element 3 9, the

downward movement of the coalesced bodies of dispersed material bydifference in specific weight is facilitated. Y

Similarly, the coalesced bodies of dispersed `material formed at the mat3l! and entrained in the liquidpassing through the sleeve 33 settle andfall through the lighter continuous phase, by d`if ference in specificWeight, vfrom the upper part of `chamber34 to the bottom part thereonThe i sleeve 33 is preferably of such length and diam- :fraction of thecoalesced bodies pass from the 'sleeve 33 at a region closely adjacentto the botvtom vpart thereof. vSuch `coalesced bodies of dispersedmaterial continue to fall through the lighter constituent of the mixtureafter being discharged from the sleeve 33 and pass into the vessel 59 inwhich the coalesced ybodies are col'- lected.

'By arranging the sleeve 3 3 within the hollovv Lmenib'er 2'5 to causethe mixture to reverse its direction of fiow at the closed end 26,'ahorizonvtally "extending path of flow is provided for the mixture inwhich minimum turbulent movement of the mixture takes place. Withminimum turbulent movement Aoi liquid in the sleeve 33, eiiectiveseparation of the coalesced bodies of dispersed material by differencein specificgravity its-.promoted In this Way a large fraction of thecoalescedbodies of dispersed material formed-at the mat settle and f allin thesleeve 33 and pass directly into the collecting vessel 59,withoutrco'ng t'a'cting or acting against the porous `sheets QD of theliquid `separating unit 35. This substantially reduces the work imposedupon the lseparating unit 35 to effect coalescing or agglomerating oithe iine liquid particles forming the dispersed phase, therebypermitting the separating lunit 35 to operate efficiently in effectingphase separationdispersed material which are of less than average sizeand also the drops of average size which are stirred `up by eddy'currents and do not setti@ immediately to the lbottom of the chamber 34 upon priming? from the Sleeve 33: The liquid `particles 10 of thedispersed phase, which are of less than average size and do not settleand fall into the bottom part of the sleeve 33, pass through the chamber34 into the inlet compartments 45 of the liquid separating unit 35.

It will be seen that an aperture E4 is provided in flange 2l in thelower or bottom part of the annular space 52. The bottom part of thespace 62 overlies the bottom part of the mat 3U. When the dispersedphase is the vheavier constituent of the mixture, it has been found thatthe coalesced liquid bodies of the dispersed phase tend to collect inthe bottom part of the space 62 above the mat 3U. Since partialsegregation or stratification o'f Such dispersed material is effected inthe space 62, the aperture 6'4 is provided whereby such coalesced liquidcan pass from space 62 directly into the larger end of chamber 34 at theregion of the collecting vessel 59 and settle in the latter. However,the aperture 54 is relatively small and liquid flows therethrough at arela# tively `slow ratel while the bulk of the mixture flows in `space62 toward the closed end 'Wall 26 of the hollow member 25.

In many instances coalesced liquid bodies or slugs of the dispersedphase `are present in the mixture introduced into the inlet space 28. Topermit such coalesced `bodies of dispersed material to collectimmediately, the vessel 5 8 is provided at the bottom part of the inletspaceV 28. The coalesced bodies `of dispersed material, when thedispersed liquid phase forms the heavier constituent of 'the mixture,settle and fall into Vthe vessel 5 8 and collect therein. The coalescedbodies of dispersed material collect in the vessels 58 andf59 anddisplace the lighter liquid `forming the continuous phase of themixture, and such coalesced liquid may be withdrawn from the apparatusi0 `from ktime to time by removing the drain plugs 50 and 6 l,respectively.

When the liquid forming the dispersed phase is thelighter constituent ofthe mixture, the apparatus I0 may b e employed equally well in suchcases by simply connecting it in place in an inverted position from that'shown in Fig. 1 In such case the drain plugs 60 and 5l Vare removedwhen the apparatus is initially placed in operaf tion to vent airtrapped in the inlet space 28 and chamber 34, and the opening B4 servesas a vent for air trapped in the annular space 62. During operation, theentire shell H including the vessels y58 and V59 is lled with liquid.When the apparatus l0 is being operated in its inverted position theoutlet 54 is preferably closed and the liquid forming the continuousphase is discharged through a conduit connected to the outlet 56, sothat such liquid will ll the chamber 53, mani-'- f old 5l and thecompartments 44 of the separating unit.

The coalesced bodies of the lighter dispersed phase entering sleeve 33rise therein during ovv of the mixture toward the vliquid separatingunit35. As previously described, the length and diameter of the sleeve 33are preferably such that the drops or coalesced liquid bodies oi averagesize can rise through a distance approximately equal to the diameter ofthe sleeve during the interval of time in which such drops move from theinlet end to the discharge end of the sleeve 33. A substantial fractionof thecoalesced liquid bodies pass from the sleeve 33 at the extremeupper part thereof and continue to rise into the collecting vessel 59without rcontacting or acting against the sheets 40 of the liquidseparating unit.

The drops of dispersed material of less than averagesize which do notrise at the same rate as the average size drops, together with thecoalesced liquid bodies of average size which are stirred up due to eddycurrents and do not rise in chamber 34, pass into the liquid separatingunit 35. Such coalesced liquid bodies passing into the liquid separatingunit coalesce and agglomerate at the surfaces of the sheets 40, and, dueto difference in specific gravity, rise through the heavier liquidforming the continuous phase. Such coalesced bodies of the dispersedmaterial also find their way into the collecting vessel 59. Thecoalesced liquid collected in vessels 58 and 59 displaces liquid formingthe continuous phase and may be withdrawn from the apparatus I from timeto time in any suitable manner, as by syphon action, for example.

When operated in its inverted position the dispersed material collectingand stratifying in the upper part of space 62 can pass through theaperture 64 directly into the enlarged end of chamber 34. While Somevliquid can pass from the space 62 through the aperture 63 when theapparatus I0 is inverted and the dispersed phase forms the lighterconstituent of the mixture, liquid flows at a relatively slow ratethrough such aperture since the bulk of the mixture in space 62 flowstoward the closed end 26 of hollow member 25, as previously explained.

If desired, provision may be made for automatically and continuouslyremoving from the apparatus I0 the coalesced liquid which collects inthe vessels 58 and 59. To effect such automatic and continuous removalof the coalesced liquid, each collecting vessel may be formed with anarrow reducedl cylindrical part` 66 which extends downwardly from thelower end thereof, as shown invFig. 6. l The part 66 at its lower end isformed with an internal shoulder 61 at the bottom side of which isdisposed a resilient sealing gasket 68 against which in turn snugly fitsa flange 69 formed at the bottom lower end of a porous member 10. Theporous member extends upwardly within the cylindrical part 66 and theupper closed end is at approximately the same level as a removablepriming plug 1| formed at the side of the cylindrical part 66.

The extreme lower end of the cylindrical part 66 is internally threadedto receive a tightening cap 12 which bears against the flange 69, and asuitable resilient sealing gasket 13 is provided between these parts. Ahollow tube 14, which is fixedv at its lower end to the cap 12 at acentral opening in the latter, extends upwardly within porous member 10and terminates ata region adjacent to the closed end thereof. A bottomcover plate 14a is threadedly secured to the bottom of the part 66 andformed with a threadedY opening to` which a drain conduit 15 isremovably secured.

The porous member 10 may be formed of ceramic material which isinherently hydrophilic and Apreferentially water wetted. Such a porousmember is suitable for automatically removing a dispersed water phasewhich collects in the vesselsv 58 and 59. When the ceramic materialforming member 10 is once wetted and the pores thereof fllledwith water,the member 10 is then conditioned so that it will be pervious to thedispersed water phase and impervious to the liquidforming-the.continuous phase and immiscible therewith.

Tofacilitate such conditioning of the member 1u for automaticallyremoving a dispersed water surface of member 10 will always bemaintained A in a wetted state and there will be no danger of the poreslosing their water filling by evaporation. While the water within member10 does not contact the extreme top inner surface thereof, the pores inmember 10 above the liquid level therein will also remain filled withliquid as a result of water working upwardly through the wall of member10 by capillary attraction or wick action.

After the porous member 10 is conditioned for use by filling the poresthereof with water, the dispersed water phase collecting in the vessel59 and passing therefrom into the cylindrical part 66 can pass throughthe member 10 into the interior thereof. Since the pores of member 10are filled with Water, the liquid formingthe continuous phase andimmiscible with water will not normally pass therethrough. So long asthe pressure differential across the wall of member 10 does not exceedthe rupture pressure, as explained above. the interface between thewater in the pores of member 10 and the liquid forming the'continuousphase will not be ruptured and the water filling the pores will not bedisplaced by the liquid forming the continuous phase.

Hence, when the dispersed water phase collects in the vessel 59 andpasses into the reduced cylindrical part 66, such Water is automaticallydischarged from the apparatus I0 due to the pressure differentialproduced across the wall of theterial like those referred to above. Insuch case,

conditioning of the porous memberl 10 by the priming plug 1I is notabsolutely necessary a1- though this may be done if desired. When thecoalesced bodies of hydrocarbon liquid collect in the vessel 59 and passtherefrom into the cylindrical part 66, such coalesced liquid bodies canfreely pass through the capillary passages of thev When the dispersedmaterial forms the lighter constituent of the mixture and the apparatusis operated in an inverted position from that shown in Fig. 1, theoverflow tube 14 is not necessary within the porous member 10 since suchporousv member will always remain filled with liquid forming thedispersed phase when such liquid is being' automatically discharged fromthe apparatus. It

is to be understood that provision may be made.

for automatically discharging the dispersed liquid from both of thevessels 58 and 59 or either ves--l sel alone.

It will now be understood that apparatus hask been provided for treatingemulsions and .otherl mixtures vof immiscible liquids for removing from13A a continuous phase another liquid immiscible therewith. Theapparatus Il] is extremely compact `and eflicient in operation, theliquid separating unit 35 presenting to the mixture a large overall areaof porous wall surfaces which occupies a minimum amount of space. Forexample, a particular installation generally like that illustrated anddescribed is capable of treating 1000 gallons of gasoline per hour andeffectively removinga dispersed water phase therefrom. The overalllength of such apparatus is about 32 inches, the diameter of the shellII is about 8 inches and the overall height including the collectingvessels 58 and 59 is about 15 inches.

'I'he apparatus I0 is so constructed and arranged that the liquidseparating unit 35 may be removed for cleaning and inspection Withoutdisturbing the outlet connection 54. When it is desired to remove theseparating unit 35 from the shell I I, the end plate is removed afterwhich the enlarged plate 36 is disconnected from the flanged end of thecentral section I2. The separating unit 35 can thus be removed from theend of the casing through the end section I5 as a single element ormember. Likewise, when it is desired to inspect the coalescing andfiltering unit 22, the end section I4 may be disconnected and removedwithout disturbing the inlet connection at 24. The end section I4 of theshell I I is of such length that when it is disconnected from thecentral section I2, a major part of the hollow member is accessible sothat the mat 3D can readily be replaced with a fresh mat or body ofporous material when this becomes necessary.

The liquid separating unit is a rigid and compact structure and of suchconstruction that the sheets 40 are effectively held between the spacerelements 38 and 33. Thus, by providing apertured bosses 41 for thespacer elements 38 which arev slotted at 4B intermediate the facesthereof, the sheets are acted upon by parts of the spacer elements 38which are adjacent to and in alignment with the apertured bosses 49 ofthe spacer elements 39. In this way a liquid tight seal is insured atthe regions the continuous liquid phase In each application or use ofthe apparatus.

I0 just described vporous sheets 4D are preferably employed inthe liquidseparating unit 35 which are, formed with capillary passages of maximumsize to Aobtain optimum ow therethrough of the4 liquid for-ming thecontinuous phase of the mixture of immiscib-le liquids. This maximumsize ofthe capillary passages is dependent upon a number -of factors, aspreviously explained, which includes lthe interfacial tension of theimmiscible liquids and the pressure diii'erential adapted to beproduced-across the porous sheets. The pressure differential adapted tobe produced across the porous sheets will always be in a pressure rangebelow and approaching` the rupture -pressure, `as previously explained,so that the only liquid passing through the capillary passages will be:the liquid to which the porous sheets are pervious.

While a single embodiment of the invention has been shown and described,it will be obvious to those skilled in the art that various changes andmodifications may be made without departing .from the true spirit andscope of the invention, as pointed fout in the following claims.

Whatis claimed is:

1. In the art of separating a mixture of liquids in which a rst liquidis present in fine particles in a second liquid immiscible therewith,the improvement which comprises the steps of passing the mixture througha body of porous material to effect mechanical coalescing o theparticles so as to form coalesced bodies of the iirst liquid, thereafterforcing thel lmixture against a porous wall member which is imperviousto the first liquid and pervious to the second liquid so as to causeflow of the second liquid through such wall member and effect final orresidual coalescing of the particles at such member to form coalescedbodies of the first liquid, said liquids being separated by differencein specific weight as the coalesced bodies of the first liquid are heldback by the porous wall member, said improvement further including thestep of flowing the mixture from the body of porous material to the wallmember in an lelongated path of flow removed from proximity to theporous wall member and from which the c0- alesced bodies of thefirst-liquid may separate by gravity while moving in the generaldirection of flow of the mixture so that at least some of the coalescedbodies of the iirst liquidl formed at the body of porous material avoidacting against the porous wall member. i

2. In the art of separating from a first liquid forming a heaviercontinuous phase of an emul-f sion e. lighter second liquid forming adispersed phase therein, the improvement which comprises the steps ofpassing a mixture of immiscible liquids forming such emulsion through abody of porous material to eiiecimechanical coalescing oi' the dispersedphase so as to form coalesced bodies of the second liquid, thereafterforcing the mixture against a porous wall member which is impervious tothe second liquid and pervious to the rst liquid so as to cause flow ofthe first liquid through such wall member andv effect final or residualcoalescing of the dispersed phase at such member to form coalescedbodies of the second liquid, collecting at an upper level of the mixtureiiowing from thebo'dy of porous material to said wall member the lightercoalesced bodies of the second liquid rising `through the mixture, andwithdrawing the coalesced second liquid collecting at theupper level ofthe mixture, said improvement 'further including the step of flowing themixture from the body of porous material to the porous wall member in anelongated path of flow out of proximity with the wall member and inwhich rise of the coalesced bodies is promoted in a path generally thesame as that of the mixture so that at least some of the coalesoedbodies of the second liquid formed at the body of porous material passto said Lipper level of the mixture and avoid acting against said porouswall member.

material to eiiect mechanical coalescing of thedispersed phase so as toform coalesced bodies' ofthe second liquid, thereafter forcing themixture against a porous wall member which is impe-rvious to the secondliquid and pervious to the first liquid so as to cause flow of the iirstliquid through such wall vmember and effect final or 3. In the art ofseparating from a vfirst liquidforming a lighter continuous phase of anemul residual coalescing of the dispersed phase at such member to formcoalesced bodies of the second liquid, collecting at a lower level ofthe mixture flowing from the body of porous material to said wallmembervthe heavier coalesced bodies of the second liquid falling throughthe mixture, and withdrawing the coalesced second liquid collecting atthe lower level of the mixture, said improvement further including thestep of flowing the mixture from the body of thevporous material to theporous wall member in an elon gated path of flow out of proximity withthe wall member and in which settling or falling of the coalesced bodiesis promoted by gravity in a path generally the same as that of themixture so that atleast some of the coalesced bodies of the secondliquid formed at the body of porous material pass to said lower level ofthe mixture and avoid acting against the porous wall member.

4. Apparatus for coalescing the dispersed phase of an emulsioncomprising a horizontally disposed elongated outer shell and ahorizontally extending inner annular-shaped hollowmember therein havinga closed end adjacent to and spaced `from an end wall of said shell andcooperating with the latter at its opposite end to forma space whichextends about thesideI and closed end of said hollow member, said shellhaving an inlet communicating with said space for introducing anemulsion therein under pressure, said hollow member having Va perioratesection which extends from a region adjacent to the closed end thereoftoward its opposite end, means including a mat of loosely packed fibersdisposed about and g overlying the perforate section of said hollowmember; and through which the emulsion is adapted'to pass from saidspace to the interior of said hollow member to effect coalescing of thedispersed phase, and a hollow open-ended sleeve coaxially disposedwithin said member and spaced therefrom to form an annular passagetherebetween, Ysaid sleeve having one end adja cent to and spaced fromthe closed end of said member, and means communicating with the oppositeend of said sleeve for withdrawing liquid therefrom.

5. Apparatus for treating a mixture of immiscible liquids comprising ashell including a central section and first and second end sectionsremovably connected thereto, said first end section being cup-shaped andhaving a closed end thereof forming an end of the shell. said secondsection having a removable end plate forming the opposite end of theshell, said central section having a pair of spaced apart inwardlyextending flanges, an open-ended sleeve disposed within said first endsection which is'secured at one end thereof to one of said iianges, saidsleeve communicating with said central section and forming therewith achamber, a hollow annularshaped member disposed between the sleeve and'first end section, said hollow member having an open end thereof Securedto said one ang-e and an opposite closed end thereof spaced from andclosely adjacent to an open end of said sleeve, said hollow memberhaving a perforate section, a mat of loosely packed fibers disposedabout and overlying said perforate section, said hollow membercooperating with said shell to form an inlet space for the mixture ofimmiscible liquids adapted to be treated, said shell having an inlet forintroducing the mixture tc said inlet space, a liquid separating unitdisposed within said central section, said unit being removably securedto said other flange and insertable into position in said shell andremovable therefrom through said second end section upon removal of saidend plate associated therewith, said liquid separating unit includingporous material forming a wall of said chamber which is pervious to theliquid forming the continuous phase of the mixture and impervious to thejother liquid immiscible therewith, said second end section having anvoutlet for discharging the continuous phase from the shell, and meansfor withdrawing from said shell the other liquid which is adapted to beheld back by the liquid separating unit.

6. Apparatus as set forth in claim 5 in which the inlet is provided insaid central section and the outlet is provided in said second endsection so that said iirst end section and said end plate may be removedwithout disturbing the connections adapted to be made at thefinlet andoutlet.

7. Apparatus as set forth in claim 5 in which said one flange isprovided with an 'aperture for venting air into the central section fromthe space between said sleeve and said hollow member, and said centralsection and iirst end section are provided with openings havingremovable closure members therefor to vent air from said inlet space andsaid chamber.

8. In apparatus for separating a pluralityY ofv horizontally extendingbaiie in said center sec" tion adjacent said member to form a horizontalilow path for said liquids, a separating membrane, means to mount saidseparating membrane between said center section and said other endsection, said separating membrane being pervious to one liquid andimpervious to the other, and a sump in said center section to collectthe one of said liquids whichvhas passed throughsaid brous membrane andis withheld by saidseparating membrane; v

9. In apparatus for separating a mixture of a plurality of immiscibleliquids having different specic gravities, structure providing ahorizontally extending chamber having an inlet adjacent one end and anoutlet adjacent the other end, a perforated partition in said structureadjacent said one end of said chamber and beyond said inlet, a fibrouscoalescing membrane, means to mount said membrane to cover theperforations in said partition whereby the mixture ow.

ing into said chamber must pass said membrane to ccalesce one of theliquids of said mixture, a separating membrane pervious to the lighterliquid and impervious to the heavier liquid of said mixture, means tomount said separating membrane across said chamber adjacent said outlet,whereby liquid flowing from said coalescing membrane to said separatingmembrane must travel in an elongated horizontal path 'so that themajority of said heavier liquid may settle by gravity to the lowerportion of said chamber prior to the time it reaches said separatingmembrane, and an outlet in the lower portion of said chamber for theheavier liquid which has settled out of said mixture. I

10. In apparatus for separating a mixture of immiscible liquids havingdiierent specific gravities, the combination of structure forming ahorizontally disposed chamber having an inlet adjacent one end and anoutlet adjacent the other end whereby liquid flowing through saidchamber must travel in an elongated horizontal path, a fibrous membrane,means to mount said membrane adjacent the inlet end of said chamberwhereby all of the liquid must pass through it, a separating membraneimpervious to one of the liquids and pervious to the other, means tomount said separating membrane adjacent the outlet of said chamber sothat all of the liquid passing through the outlet must go through saidseparating membrane, the arrangement being such that the majority of theheavier liquid will settle to the bottom of the chamber as it moveshorizontally through said chamber between said two membranes to therebyreduce u the amount of separating that must be done by 18 REFERENCESCITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 813,014 Merrill Feb. 20, 19061,194,949 Burchenal Aug. 15, 1916 1,227,999 Dameron May 29, 19171,242,784 Dyer et al Oct. 9, 1917 1,331,732 Wait Feb. 24, 1920 1,494,677Feldmeier May 20, 1924 1,663,322 Tekavec Mar. 20, 1928 1,787,577 HillsJan. 6, 1931 2,186,501 Seligman et al Jan. 9, 1940 2,359,386 ReinschOct. 3, 1944 2,390,628 Van Winkle Dec. 11, 1945 2,404,872 Walker July30, 1946 FOREIGN PATENTS Number Country Date 602,788 France Mar. 26,1926

